EL is a phospholipase that belongs to triglyceride lipase (hereinafter, referred to TG) family (non-patent literature: 1). Human EL consists of 500 amino acids (NCBI Accession number NP_006024.1, SEQ ID NO: 1) and rabbit EL consists of 500 amino acids (NCBI Accession number NO_001182567, SEQ ID NO: 2). Lipoprotein lipase (hereinafter, referred to LPL) and hepatic lipase (hereinafter, referred to HL) is contained by TG family.
The analysis of EL knockout mouse and EL transgenic mouse revealed that EL relates to HDL cholesterol (hereinafter, referred to HDL-c) metabolism by its strong phospholipase activity, and have been a focus as a factor which controls HDL-c level in blood (non-patent literature: 2). It has been well-known that there is a negative correlation between coronary artery disease (hereinafter, referred to CAD) and HDL-c level in blood. HDL-c shows anti-atherogenic effect through antioxidant effect, anti-inflammatory effect and reverse cholesterol transport and so on, low HDL-c emia is recognized as one of the risk factor of CAD. Therefore, EL inhibitor could become a therapeutic agent for CAD through increasing HDL-c in blood. In fact, it was reported that lesion mouse of EL knockout increased HDL-c and decreased atherosclerotic lesions (non-patent literature: 3).
These findings indicate that a selective EL inhibitor is useful as therapeutic agent for abnormality of lipid metabolism and arteriosclerosis.
A selective inhibition of EL is useful as therapeutic agent for abnormality of lipid metabolism and arteriosclerosis, so a production of EL antibodies which inhibit EL activity is one of the important approaches. So far, it has been reported that a rabbit polyclonal antibody which inhibits EL activity was prepared, HDL-c level in mouse blood increased after administrating of the antibody (non-patent literature: 4).
Polyclonal antibodies recognize various regions of EL and do not have a high selectivity against EL. Also, it is impossible to use rabbit anti-EL polyclonal antibodies having high immunogenicity to human as therapeutic agent for chronic diseases because therapeutic agents for chronic diseases such as the abnormality of lipid metabolism and arteriosclerosis related to EL have to be administrated for a long term. Moreover, it is difficult to manipulate immunogenicity of polyclonal antibodies.
By these circumstances, a monoclonal antibody inhibiting selectively the enzymatic activity of EL is awaited.    Non-patent document 1: Nature Genetics., 1999, vol. 21, p. 424    Non-patent document 2: TCM., 2004, vol. 14(5), p. 202-206    Non-patent document 3: The Journal of Biological Chemistry., 2004, vol. 279, No. 43, 22 p. 45085-45092    Non-patent document 4: J. Clin. Invest., 2003, Vol. 111(3), p. 357